Buffer Lost To Exec

Compiled and run with stdout attached to a terminal, so stdio is line buffered.

#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>

int main(void) {
    printf("A");
    pid_t p = fork();
    if (p == 0) {
        printf("B");
        execlp("echo", "echo", "C", (char *)NULL);
        printf("D");
    }
    wait(NULL);
    printf("E\n");
}

What appears on the terminal?